Stirring device



y 1963 F. H. DEINDOERFER 3,088,715

STIRRING DEVICE Filed Aug. 11, 1959 ATTORN EYS United States Patent 3,088,715 STIRRING DEVICE Fred H. Deindoerfer, 61 Chester Circle, New Brunswick, NJ. Filed Aug. 11, 1959, Ser. No. 833,079 6 Claims. (Cl. 259-72) The present invention relates to a stirrer for use in flasks or the like which are employed in microbiological and chemical operations and the like.

The purpose of the invention is to facilitate stirring by increasing the turbulence in a shaken flask, without the need to introduce projections from the flask wall itself.

A further purpose is to provide a foldable organic plastic stirrer which will collapse to introduce into a flask through the neck and which will extend by its own resilient recovery to occupy the radial distance at the bottom of the flask to a position adjoining the side walls and provide upstanding vanes.

A further purpose is to provide a stirrer of the character in question which can be retained in the flask during cleaning and during sterilization.

Further purposes appear in the specification and in the claims.

In the drawings I have chosen to illustrate a few only of the numerous embodiments in which the invention may appear, selecting the form shown for convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

FIGURE 1 is a central vertical axial section through a flask provided with a stirrer of the invention.

FIGURE 2 is a top plan view of the stirrer of 'FIG- URE 1 in expanded position.

FIGURE 3 is a perspective showing the stirrer of FIGURE 1 collapsed and about to be inserted through the neck of a flask.

FIGURE 4 is a central vertical section through a flask showing a modified stirrer according to the invention in place in the flask.

FIGURE 5 is a top plan view of the stirrer of FIG- URE 4 in expanded position.

FIGURE 6 is a central vertical section of a flask containing a further modified stirrer of the invention.

FIGURE 7 is a top plan view of the stirrer of FIG- URE 6 in expanded position.

Describing in illustration but not in limitation and referring to the drawings:

In microbiological operations, such as bacteriological, and mycological operations, growth of viruses, submerged culture of mammalian tissue, and the like, and also in chemical laboratory operations, it is frequently desirable to be able to increase the turbulence in a flask which is shaken or vibrated, as on a platform, by providing projections on the flask interior.

One practice has been to heat portions of the flask wall and form projections of the glass wall into the flask by glass working. This is a very tedious job. If it is not carefully carried out, it may cause undue thinning of the wall of the flask or introduce unequal stresses, which will weaken the flask and cause it to break readily. Presence of the projections on the interior of the flask also greatly complicates the problem of cleaning the flask.

In accordance with the present invention, a pliable organic plastic stirrer is introduced into the flask, by collapsing the stirrer so that it will pass through the neck, and allowing the stirrer to expand under its resilient recovery and extend readily out to a position adjoining the side walls, while erecting desirably generally vertical vanes.

3,088,715 Patented May 7, 1963 ice The flask involved may be of any suitable shape, the convenient form being an Erlenmeyer, although Florence and Fernbach flasks are also used.

The organic plastic employed for the stirrer will suitably be one which has the desired stiffness when in place, but has elastomeric properties so that it will recover its shape after being collapsed.

The organic plastic should also be substantially inert to the biological organisms or chemicals being used. The organic plastic should also be preferably inert to cleaning solutions and capable of withstanding sterilization.

A very desirable plastic material is polytetrafluorethylene (Teflon) or a grade of polyethylene or polypropylene which will withstand heat sterilization. Other organic plastic material may be used especially where heat sterilization is not required. Suitable examples are natural rubber, neoprene, and polyvinyl chloride.

The surfaces of the stirrer should preferably be smooth so that cleaning of the stirrer will be easy.

As best seen in FIGURES 1 to 3, I illustrate an Erlenmeyer flask 20 having a bottom 21, conical sides 22, a neck 23, and an entering lip 24.

The stirrer, a single piece of organic plastic in the preferred embodiment, includes in its expanded position, a series of suitably vertically extending vanes 26, conveniently equally spaced around the circumference as shown. The vanes are suitably thin sheets of the plastic. The vanes are desirably tapering to conform generally with the taper of the flask side wall at their outer edges 27, and to suitably fit against the bottom at their bottom edges 28, terminating away from the center in suitably vertical interior edges 30.

The vanes are connected and held in their proper position by a lower plastic ring 31 extending around the interior, and by an upper plastic ring 32 extending around the interior, leaving an open interior portion 33.

The vanes extend up high enough to rise above any normal charge that will be placed in the flask, so that they will interrupt the liquid surface in this form and promote interphase mass transfer between the gaseous phase above the surface, and the liquid such as in heterogenous chemical reactions or in aerobic fermentations.

In operation, using the device of FIGURES 1 to 3, the stirrer is simply collapsed as shown at 25 in FIG- URE 3 and pushed down through the neck, bottom first. When it reaches the bottom of the flask the resilient recovery of the plastic material causes it to recover its expanded position as shown in FIGURE 1. When the flask is shaken or vibrated, turbulence will occur, breaking up any tendency for a mass swirling action which might otherwise take place. Thus very effective stirring is accomplished by the vanes which direct flow of liquid from one separation to another of the flask through the interior space 33.

In the preferred embodiment, the vanes slightly resiliently engage against the inside and bottom of the flask and this tends to hold the vanes in place.

After the flask has been used and is about to be cleaned, the user may, if he desires, pull out the stirrer by collapsing it, using a finger or a hook to grasp the stirrer, in which case the flask can be cleaned by usual techniques, and the stirrer can be cleaned independently and then reused. In some cases, it may be preferable to clean the flask and also heat sterilize while the stirrer is in place and in this case the stirrer composition should be such that it will withstand the cleaning solution and the sterilization in the flask if this is required.

In many cases, it is not important to have the stirrer extend high in the flask as the charge will be concentrated in the bottom of the flask.

3 I illustrate in FIGURES 4 and 5 a stirrer having radially expanding and upwardly extending vanes 2d, of

which suitablyfou'r are shewn, havingan outer edge 27' which engages the inside of the side wall, and having a bottom 28 which conforms to the bottom wallbut is 'spaced therefrfornyby a b'ody consisting of an integral plastic ring 31" at the bottom, and also by an integral plastic pedestal 34'atthe center. i

The tops of the .vanes taper downwardly from a high position at the outer edge to a minimum near the center along the edges'35' and the vanes connect at the center with pedestal 34. i V

This unitary molding is inserted in the flask in the same manner as already'described, and it causes turbulence in the liquid content when the flask is in motion, while permitting'fl'ow from one'side to the other side of the vanes in the spaceb'ene'ath the vanes and also near the center.

In some cases it is desirable to provide more communicationnear the'center between various quadrants and this is accomplished in the form of FIGURES 6 and 7 where vanes 26 extend radially and upwardly and have outer edges 27 which engage and suitably pressslightly against the side wall of the flask andbottom edges 28 which engage and suitably press slightly against the bottom of the flask.

The vanes have vertical inner edges 30, and have suitable flat tops 36 The vanes at theirvertical. inner edges are cross-connected by 'anintegral plastic ring 31 so that the stirrer has an open Center.

In operation; the form of FIGURES 6 and 7 is similar to that already described. It'will be understood that in other forms of flask thes-tirrerwill suitably 'be'modifiedto conform to the walls of the flask.

In viewof my invention and disclosure variations and modifications to meet individual whim orparticillar need will doubtless become evident to" others skilled in the art, to obtain all 'or part of the benefits of my invention without copying the structure shown, and I therefore,

4 claim all such insofar as they fall within the reasonable pirit ans! .9929 9f m 21m:

Having thus described my invention what I claim as new and desire to secure byILetters Patent is:

1. A flask and stirrer assembly including a flask having an enlarged body portion and a restricted neck, a stirrer resting on the bottom of the flask and comprising a pliable'organic plastic body having a size larger than the neck of theflask, a plurality of upstanding vanes connected to the body and extending to the side walls of the flask, the stirrer having a collapsed position in which it is adapted to enter the neckof the flask and an expanded position in which it substantially occupies the radial extent of the bottom of the flask, said stirrer lying wholly within the flask during use and remain fixed with respect to the flask.

2. A stirrer of claim 1, in which the stirrer has an open center.

3. A stirrer of claim 1, in which the said vanes in the extended position extend radially of the flask.

4. A'stirrer of claim 1, in which the said body includes a plastic ring.

SfAfstirrerfof "claim 1, in which said vanes connect at the center of the stirrer.

6. A stirrer of claim 1, in which said body includes aring of plastic and said vanes extend outwardly and upwardly from said ring.

References Cited in the file of this patent UNITEDSTATES PATENTS 2,592,485 Stair Apr. 8, 1952 2,859,020 Eddy et al. Nov. 4, 1958 FOREIGN PATENTS 148,968, Austria Mar. 25, 1937 656,244 GreatyBritain Feb. 6, 1952 793,021 Great Britain Apr. 9, 1958 

1. A FLASK AND STIRRER ASSEMBLY INCLUDING A FLASK HAVING AN ENLARGED BODY PORTION AND A RESTRICTED NECK, A STIRRER RESTING ON THE BOTTOM OF THE FLASK AND COMPRISING A PLIABLE ORGANIC PLASTIC BODY HAVING A SIZE LARGER THAN THE NECK OF THE FLASK, A PLURALITY OF UPSTANDING VANES CONNECTED TO THE BODY AND EXTENDING TO THE SIDE WALLS OF THE FLASK, THE STIRRER HAVING A COLLAPSED POSITION IN WHICH IT IS ADAPTED TO ENTER THE NECK OF THE FLASK AND AN EXPANDED POSITION IN WHICH IT SUBSTANTIALLY OCCUPIES THE RADIAL EXTENT OF THE BOTTOM OF THE FLASK, SAID STIRRER LYING WHOLLY WITHIN THE FLASK DURING USE AND REMAIN FIXED WITH RESPECT TO THE FLASK. 